Sensational!

This can be extremely easy if you have the right upgrades, Purchase the Demon Evade Ability, the Trinity Smash combo for the Arbiter, and Trinity Smash Level 2. Wait for any group of enemies to come by to do this. Evade with the Demon Evade Ability just before a demon hits to power up Dante, then use the Trinity Smash combo to instantly get a SSS Rank. It's that simple!

If the enemies die too quickly, find a bigger group, or up the difficulty.

Make sure to set your difficulty to human (easy) difficulty and start mission 11. In the very beginning you will have to fight several Stygians. Start with an Arbiter Tremor (R2+Circle on PS3 / RT+B on X360), followed by an Osiris Karma attack (L2+Triangle on PS3 / LT+Y on X360). Switch to the Aquila for a few strikes and you should already have the SSS bonus. Try to hit as many enemies as possible with every attack and avoid repeating the same move.Restart the mission if all enemies die before you get the SSS Style Rank.